An optimized upper divertor with divertor-coils to study enhanced divertor configurations in ASDEX Upgrade

A new upper divertor with in-vessel coils to investigate 'advanced' magnetic configurations will be installed in ASDEX Upgrade. 'Advanced' magnetic configurations are part of a risk mitigation strategy should the conventional divertor configuration approach not be applicable for future fusion reactors. The concept of the new upper divertor, Div-IIo, consists of an outer divertor with embedded divertor coils, an inner divertor and a cryo pump with 15 m(3)/s effective pumping speed in the private flux region. The new divertor coils will be designed for 50 kAt and can be operated with 5 s plateau phase. This paper presents the design concept of the divertor and coil support structure, the coils and the cryo pump. In addition the forces to the divertor structure due to normal operation and during disruptions are discussed. (C) 2017 Elsevier B.V. All rights reserved.